A gas turbine engine generally includes a compressor section, a combustion section, a turbine section, and an exhaust section. The compressor section progressively increases the pressure of a working fluid entering the gas turbine engine and supplies this compressed working fluid to the combustion section. The compressed working fluid and a fuel (e.g., natural gas) mix within the combustion section and burn in a combustion chamber to generate high pressure and high temperature combustion gases. The combustion gases flow from the combustion section into the turbine section where they expand to produce work. For example, expansion of the combustion gases in the turbine section may rotate a rotor shaft connected, e.g., to a generator to produce electricity. The combustion gases then exit the gas turbine via the exhaust section.
The turbine section generally includes a plurality of rotor blades. Each rotor blade includes an airfoil positioned within the flow of the combustion gases. In this respect, the rotor blades extract kinetic energy and/or thermal energy from the combustion gases flowing through the turbine section. Certain rotor blades may include a tip shroud coupled to the radially outer end of the airfoil. The tip shroud reduces the amount of combustion gases leaking past the rotor blade.
The rotor blades generally operate in extremely high temperature environments. As such, the airfoil and tip shroud of each rotor blade may define various passages, cavities, and apertures through which cooling fluid may flow. For example, one or more cooling passages may extend through the airfoil to supply the cooling fluid to a core in the tip shroud. The cooling fluid then exits the core through one or more outlet apertures in the tip shroud. All cooling fluid flowing to the tip shroud may be directed to the core. Nevertheless, the outlet apertures in the tip shroud create back pressure in the rotor blade, which reduce the velocity of the cooling fluid flowing therethrough. This reduced velocity may limit the cooling provided to certain portions of the airfoil.